PORTLAND, Ore. (KOIN) — Oregon Health Authority has issued a Recreational Health Advisory for the Willamette River, near Cathedral Park in North Portland, due to harmful cyanotoxins, the Oregon State Marine Board announced Wednesday.

According to the Marine Board, cyanotoxin levels in the river are above safe recreational levels for humans.

Health officials say people should avoid swimming and other activities such as water skiing or power boating in the area where the blooms are, due to the risk of ingesting water.

OHA said boating is safe as long it doesn’t create excessive water spray.

While the advisory is limited to the Cathedral Park area, officials said the toxins may spread downstream.

Symptoms from ingesting cyanotoxins include food poisoning symptoms such as stomach cramping, diarrhea, nausea and vomiting. Other symptoms include numbness, dizziness and shortness of breath.

OHA noted children and pets have an increased risk for exposure because of their size and levels of activity.

“Dogs can get extremely ill and even die within minutes to hours of exposure to cyanotoxins by drinking the water, licking their wet fur or eating the toxins from floating mats or dried crust along the shore. This is regardless of a recreational use health advisory in place,” OHA said.

Cyanotoxin exposure in dogs may include symptoms such as lethargy, difficulty walking, seizures and loss of appetite. OHA says dogs should be taken to a veterinarian as quickly as possible for these symptoms.

Officials will collect samples in the next few days to “better define the extent of the public health advisory.”